Why does the printer smudge paper?

Question

Printers

Hello!
The Kyocera FS-1030MFP KX printer began to smudge paper after using a cartridge that was filled with toner from another (I didn’t do this, and don’t ask why).
The problem manifests itself in:
1) A thin layer of gray ink on the sheet when printed. Those. the background of the document becomes gray instead of white.
2) A large strip on the back of the sheet, which is not printed, but simply gets dirty (ie, can be wiped off with a napkin).
I thought that it would go away after replacing the cartridge, but no. It did not pass.
Tell me, please, what can be done in this case yourself?

Answer 1

take the printer in for service. let them clean it up. Well, if you get off with only prevention.
inside most likely you also have https://youtu.be/487Us813vwY?t=799

Answer 2

In kiosires there is a separate cartridge: a tube, a developing unit, a photodrum unit.
Nothing will change from the fact that you replaced the tube, since the developing unit always has toner from the previous tube. Tubes can only be used with the same toner, otherwise you will have to reclean the development unit.